From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161570Ab2GMOCy (ORCPT ); Fri, 13 Jul 2012 10:02:54 -0400 Received: from smtp3.mundo-r.com ([212.51.32.191]:10787 "EHLO smtp4.mundo-r.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750967Ab2GMOCw (ORCPT ); Fri, 13 Jul 2012 10:02:52 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AjUMAB0qAFBbdWOb/2dsb2JhbABFr1oiiCSBB4IgAQEEATIBBR0jAQULCxgJFg8JAwIBAgFFBg0BBwEBiAMKu1uLPIV2A5U6iSaGYIJh X-IronPort-AV: E=Sophos;i="4.77,580,1336341600"; d="scan'208";a="1018986805" Message-ID: <50002A76.6000609@igalia.com> Date: Fri, 13 Jul 2012 16:02:30 +0200 From: =?ISO-8859-1?Q?Miguel_G=F3mez?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120615 Thunderbird/13.0.1 MIME-Version: 1.0 To: Greg KH CC: arnaud.patard@rtp-net.org, aaro.koskinen@iki.fi, dan.carpenter@oracle.com, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/19 v2] Staging: xgifb: Remove LCDA detection in xgifb_probe(). References: <0b5331426e8c4fc37b62c58e052526c8c4a28495.1341569486.git.magomez@igalia.com> <20120709183947.GA21153@kroah.com> In-Reply-To: <20120709183947.GA21153@kroah.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org El 09/07/12 20:39, Greg KH escribió: > On Fri, Jul 06, 2012 at 12:40:38PM +0200, Miguel Gómez wrote: >> The piece of code that checks for LCDA in xgifb_probe() just checks for some >> register values but doesn't really do anything in response to them (the actions >> that should be executed are commented). >> As nothing is really being done, the code can be safely removed. > > Are you sure? Some devices (foolish ones that is) need registers read > to work properly as that is part of their start-up logic. Yeah, it > doesn't seem to make sense, but hardware designers usually have good > reasons for doing this type of thing. Or at least they think they do :) Weird... I didn't expect that some devices might need those reads to work properly... I'm writing down that comment for the future ;) > So have you tested the device after this change and it all works > properly? You do have this device, right? I have an XGI Z7 card that I use for testing, and it doesn't require those reads to work properly, despite I don't have a Z9 or Z11 to test. But according to Aaro's comment, it seems that the patch is safe as these register reads don't have any effect. Regards! -- Miguel Gómez Igalia - http://www.igalia.com